A conventional coated cutting tool used for the cutting of steel, cast iron, etc., is a coated cutting tool which is obtained by depositing, via chemical vapor deposition, a coating layer with a total thickness of from 3 μm or more to 20 μm or less on a surface of a substrate consisting of a cemented carbide. A known example of the above coating layer is a coating layer consisting of a single layer of one kind selected from the group consisting of a Ti carbide, a Ti nitride, a Ti carbonitride, a Ti carboxide, a Ti carboxynitride, and aluminum oxide, or consisting of multiple layers of two or more kinds selected therefrom.
JP4739235 B discloses a coated cutting tool comprising a substrate and a coating formed on the substrate, wherein: the coating includes a first coating comprised of TiCN and a second coating comprised of α-type Al2O3; the first coating has tensile stress S1 and the second coating has compressive stress S2; and the tensile stress S1 and the compressive stress S2 satisfy the relationship of 400 MPa≤|S2−S1|≤3,500 MPa.
JP4739236 B discloses a coated cutting tool comprising a substrate and a coating formed on the substrate, wherein: the coating includes a first coating comprised of TiCN and a second coating comprised of α-type Al2O3; the first coating has tensile stress or is released from tensile stress to substantially have no stress; the second coating has compressive stress S1 on a rake surface and tensile stress S2 on a flank; and the compressive stress S1 and the tensile stress S2 satisfy the relationship of 441 MPa≤|S1−S2|≤3,500 MPa.